<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./js/vue2.js"></script> 
</head>
<body>
    <div id="app">
   <input type="text" v-model='count'>
    <p>你的成绩等级是:</p>
    <div v-if='count>=90'>A</div>
    <div v-else-if='count>=80'>B</div>
    <div v-else-if='count>=70'>C</div>
    <div v-else-if='count>=60'>D</div>
    <div v-else>E</div>
</div>


    <script>
        var vm = new Vue({
            el:'#app',
            data:{
                count:0
            }
        })
        </script>
</body>
</html>